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BOUNDARY LAYERS

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                                                   BOUNDARY LAYER FLOWS   Introduction: When real fluid flow past a solid body or a solid wall, the fluid particles adhere to the boundary and condition of no slip occurs. This means that the velocity of fluid close to the boundary will be same as that of the boundary. If the boundary is stationary, velocity of fluid at the boundary will be zero. Further away from the boundary, the velocity will be higher and as a result of this variation of velocity,   the velocity gradient du/dy   will exist. The velocity of fluid increases from zero velocity on the stationary boundary to free-stream velocity (U) of the fluid in the direction normal to boundary condition take place in a narrow region in the vicinity of solid boundary. This narrow region of fluid is called boundary layer. The theory dealing with boundary layer flows is called boundary layer theory, the flows of fluid in neighborhood of solid boundary may be divided into two regions